The present invention relates to a power train for a motor vehicle. More particularly, the invention relates to a power train that allows a starter/generator to drive a transmission pump and to selectively engage an internal combustion engine.
Vehicle transmissions include an internal combustion engine, a starter/generator, and a transmission input. Incorporating a starter/generator into a transmission presents several issues. For example, crankshaft-mounted starter/generators add a large mass, i.e., the mass of the rotor, to the crankshaft. This adds load to the crankshaft bearings, and can exacerbate crankshaft deformation and stress due to dynamic loading. Ultimately, deformation of the crankshaft can make it difficult to maintain the small, uniform air gap desirable for the starter/generator.
The present invention provides a power train having a starter/generator that is not mounted on the crankshaft. Furthermore, the starter/generator is able to directly drive a transmission pump, and can selectively engage a torque converter and/or an internal combustion engine.
Briefly, a power train in accordance with the present invention comprises an internal combustion engine, a starter/generator that has a rotor, a torque converter, a transmission pump directly connected to the rotor, a selectively engageable clutch disposed between the starter/generator and internal combustion engine, and a transmission input directly connected to the output turbine of the torque converter.